gpu: make Adapter an enum with methods

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

gpu/src/adapter.zig

@@ -0,0 +1,40 @@
+const testing = @import("std").testing;
+const ChainedStructOut = @import("types.zig").ChainedStructOut;
+
+pub const Adapter = enum(usize) {
+    _,
+
+    pub const none: Adapter = @intToEnum(Adapter, 0);
+
+    pub const Type = enum(u32) {
+        discrete_gpu,
+        integrated_gpu,
+        cpu,
+        unknown,
+
+        pub fn name(t: Type) []const u8 {
+            return switch (t) {
+                .discrete_gpu => "Discrete GPU",
+                .integrated_gpu => "Integrated GPU",
+                .cpu => "CPU",
+                .unknown => "Unknown",
+            };
+        }
+    };
+
+    pub const Properties = extern struct {
+        next_in_chain: *ChainedStructOut,
+        vendor_id: u32,
+        vendor_name: [*:0]const u8,
+        architecture: [*:0]const u8,
+        device_id: u32,
+        name: [*:0]const u8,
+        driver_description: [*:0]const u8,
+        adapter_type: Type,
+        backend_type: Type,
+    };
+};
+
+test "Adapter.Type name" {
+    try testing.expectEqualStrings("Discrete GPU", Adapter.Type.discrete_gpu.name());
+}